The 340 6-pak and some of the 440 6-pak manifolds were aluminum and made by edelbrock. The 426 hemi had an alumium manifold don't know who made it. The cross ram manifolds on the 413 & 426 Max Wedge motors were aluminum also.
Dave is correct. The '70 model (factory production) small block, six pack, intake was made by Edelbrock. I'm not sure of all sources, but I know this can be verified in the "How To Hot Rod Small-Block Mopar Engines" book by Larry Shepard in the "induction system" chapter.
